A double­ring conductance sensor used for water holdup logging in horizontal wells

Wenfeng Xu, Lijun Xu

School of Instrument Science and Opto­Electronics Engineering, Beihang University, Beijing 100191, China

email: xuwenfeng0459@163.com, lijunxu@buaa.edu.cn Xingbin Liu, Jinhai Hu, Shuilong Ma

Production Logging Institute, Daqing Logging & Testing Services Company, Daqing 163453, China email: dlts_liuxb@petrochina.com.cn, hujinhai66@126.com, dlts_masl@petrochina.com.cn

ABSTRACT

A new production logging (PL) tool was developed for water holdup measurement in horizontal wells. The tool uses a double­ring shaped conductance array of 24 electrodes formed by 12 supporting arms to provide an excellent image of the holdup pattern. For oil/water two­phase stratified flow in a horizontal well, the oil/water interface is located by a “probe” method. An optimization program is proposed for the determination of the radiuses of the two rings and the uncertainty in estimation of the interface can be obtained easily when the “probe” method is used alone. To further improve the measurement accuracy of the interface, a least­square (LS) based method was put forward by using a sample database that was obtained in advance. The sample database of the interface was obtained through a series of static experiments. It was shown that the oil­water interface can be determined more accurate by the use of the LS method. Experiments showed that the tool can be used to measure the water holdup in horizontal wells.

Keywords Electrical conductance sensor, horizontal well, water holdup, water cut, two­phase flow